Rotating tourniquet system



United States Patent 3,465,749 ROTATING TOURNIQUET SYSTEM Stephen T. Moreland, Grosse Pointe Woods, and Walter S. Kazmierczak, Detroit, Mich., assignors to R. P.

Scherer Corporation, a corporation of Michigan Filed June 16, 1967, Ser. No. 646,617 Int. Cl. A61b 17/12 U.S. Cl. 12824 2 Claims ABSTRACT OF THE DISCLOSURE A rotating tourniquet system that has an air compressor, four pressure cults to be secured around each arm and each leg of a patient, a valve for properly distributing the air pressure to the pressure cuffs from the air compressor, and a valve for adjusting the pressure in the cuffs to a desired level. The improvement involves providing a pressure relief valve between the air compressor and the distributor valve, and the relief valve is preset to relieve the air pressure in the system when the air pressure exceeds a predetermined desired level.

BACKGROUND OF THE INVENTION Field of the invention and description of the prior art This invention relates to an improved automatic rotating tourniquet system and it particularly relates to such a system which provides a high degree of safety for the patient upon whom the equipment is being used.

U.S. Patent No. 3,167,067 shows an automatic rotating tourniquet system which has been found to be generally satisfactory. Such rotating tourniquet systems are used primarily in the treatment of pulmonary edema associated with acute left ventricular heart failure. The equipment is also used for restricting venous return, which, in turn,

decreases the overload on the left ventricle. This automatic equipment provides more precise control than manually applied tubing or blood pressure cuffs. The automatic equipment also saves the time of nurses or doctors who would otherwise be needed to manually operate tourniquets. The equipment also provides immediate venostasis and relief to the patient shortly thereafter. Further advantages include the elimination of the trauma of blood letting and the equipment may be left in the operating position for many hours at the discretion of the physician.

Although the described equipment has been found to be generally satisfactory in use, there is a significant problem encountered in adjusting the air pressure in the system. An adjustable needle valve is provided in the prior art device for adjusting the pressure in this system to the desired level. This needle valve, however, either intentionally or through negligence, sometimes permits the pressure on the arms and legs, through the cuffs, to build up to a pressure of 250 or even 270 mm. of mercury. This build up in pressure may result'frorn the air pump or, which is even more dangerous, it can be caused by the patient himself when he changes his position in a bed or in a chair. Such a change of position causes the weight of the body to be applied to the lower end of the cuff. These excessive pressures may be harmful to the patient and are uncomfortably painful.

3,465,749 Patented Sept. 9, 1969 Furthermore, the bladders in the pressure cuffs are not made to withstand high air pressures. Thus, when the pressure exceeds the desired level, not only is it dangerous and uncomfortable to the patient, but the equipment, such as the bladders, may break down so that the patient is not obtaining proper treatment. If the bladders burst from excessive air pressure, they must be replaced which is time consuming and expensive.

SUMMARY OF THE INVENTION It is therefore an important object of this invention to provide an improved rotating tourniquet system which avoids the disadvantages of prior art devices.

It is a further object of this invention to provide an improved automatic rotating tourniquet system wherein there is assurance that air pressure will not exceed a predetermined level.

It is also an object of this invention to provide an improved automatic rotating tourniquet system wherein pressure relief means are provided in the system so that the patient being treated is not subjected to a dangerous or a painful situation and there is assurance that the equipment will not malfunction by breakdown caused by excessive air pressure.

It is another object of this invention to provide an improved automatic rotating tourniquet system which provides trouble-free, safe operation in a highly simple and economical manner.

Further purposes and objects of this invention will appear as the specification proceeds.

In its most important aspect, the improved rotating tourniquet system comprises providing a pressure relief valve between an air pressure distributing valve and an air compressor, the air pressure relief valve being preset so as to relieve air pressure in the system when the system air pressure exceeds a predetermined level.

BRIEF DESCRIPTION OF THE DRAWINGS Referring to the accompanying drawings, there is shown a particular embodiment of the present invention, wherein:

FIGURE 1 is a generally schematic view of our improved automatic rotating tourniquet system;

FIGURE 2 is an enlarged detailed top plan view of the pressure relief valve used in the improved tourniquet system of FIGURE 1;

FIGURE 3 is a cross-sectional view taken along the line 3-3 of FIGURE 2 showing the internal construction of the pressure relief valve used in the system of FIGURE 1; and

FIGURE 4 is a cross-sectional view taken along the line 44 of FIGURE 2, also showing the internal construction of the same relief valve.

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings, and particularly to FIGURE 1, the improved automatic rotating tourniquet system, generally 10, is schematically shown. The system 10 includes a fractional horsepower electrical motor 12 which is desirably about of a horsepower. The motor 12 drives an air compressor 14 which causes compressed air to pass through the tubing 16. From the tubing 16, the compressed air passes through a first pressure reservoir 18 then through another section of tubing 20 and to a second pressure reservoir 22.

From the second pressure reservoir 22, the pressurized air passes to a pressure relief valve, generally 24. In FIG- URE 1, the relief valve 24 is schematically shown only, but is shown in detail in FIGURES 2-4; a detailed description of the structure of the relief valve 24 will be set forth after the description of the entire system has been provided. The relief valve 24 is connected on opposite sides of tubing sections 26 and 28. The tubing 28 is connected to one opening of a cross fitting 30.

A tubing section 32 is connected to a second opening in the cross fitting and is connected to a pressure gauge 34. A third connection of the cross fitting 38 is connected to tubing 36 which in turn is connected to a bleeder valve 38.

The bleeder valve 38 includes a handle 40 which is located in a position which is manually accessible to an operator. By manually adjusting the handle 40, the operator may set the system air pressure at the desired level by observing the pressure reading on the pressure gauge 34. The bleeder valve 38 has an outlet 42 through which pressurized air passes to the atmosphere so as to relieve and thereby maintain the pressure in the system at the desired level.

A fourth outlet on the cross fitting 30 is connected to a tubing section 44 which in turn is connected to a distributor valve 46. The distributor valve 46 is generally the type found and described in detail in the Rand Patent No. 3,167,067, referred to above. The valve 46 distributes air pressure to the cuffs 48 in the proper sequence. Since the distributor valve 46 forms no part of the present invention, there will be no detailed description of the construction or operation thereof.

From the inlet 50 of the distributor valve 46, the pressurized air passes through suitable porting Within the valve 46 and the pressurized air passes in the desired sequence through the four outlets 52 of the distributor valve 46. The four outlets 52 are each connected to four flexible tubes 54 which are connected to pressurized cuffs 48 which are wrapped around the arms and legs of a patient suffering, for example, from pulmonary edema. The distributor valve 46 is operated by a fractional horsepower motor 56 which rotates an internal valve plate (not shown) which properly distributes air pressure from the distributor valve 46 to the pressure cuffs 48.

A case 58, which is preferably portable, encloses substantially all of the operating parts of the system 10. Generally, the portable carrying case 58 encloses the distributor valve 46 and operating motor 56, the reservoirs 18 and 22, the frictional horsepower motor 12, and the air compressor 14, as well as the various tubes interconnecting these parts. Suitable apertures are provided in the Wall of the case 58 to permit the passage of the flexible tubes 54 therefrom to the pressure cuffs 48. A suitable aperture is also provided for positioning the bleeder valve 38 on the exterior of the case 58. The pressure gauge 34 is also locataed on the exterior of the case 58.

As is known, when it is desired to operate the system 10, the operator causes the distributor motor 56 and the air compressor motor 12 to start so that the valve 46 distributes the pressurized air from the air compressor 14 to the pressure cuffs 48. The operator then, by rotating the handle 40, adjusts the bleeder valve 38 by observing the pressure gauge 34, to the desired level. The pressure cuffs 48 are placed around the patients arms and legs and the system is in operation.

The problem encountered in the past has been that if the operator forgets to adjust the bleeder valve 38 or fails to properly adjust the bleeder valve 38, the pressure can build up excessively high in the system 10 and cause discomfort for or create a dangerous situation with the patient or the bladders (not shown) in the pressure cuffs 48 may burst from excessive air pressure. The breaking of the bladders is an undesirable situation since this causes the equipment to malfunction and the patient is not getting the treatment which he needs. Also, even if the bleeder valve is set at the desired level, when the patient turns in such position that undue weight is placed upon the pressure cuffs 48, the pressure can build up to an undesired level to cause bursting of the bladders in the cuffs 48 or to cause discomfort or a dangerous situation for the patient. It is for these reasons that it is important that the pressure relief valve 24 be interconnected in the system 10 between the air compressor 14 and the distributor valve 46.

Referring to FIGURES 2-4, the internal construction of the relief valve preferably used in our construction is shown in detail. An outer cylindrical body 60 defines the exterior of the relief valve 24. A reciprocal piston 62 is mounted within the hollow substantially cylindrical chamber 64 within the valve body 60. The lower portion of the piston 62 includes a chamfered or frusto-conical surface 66 which abuts against a mating chamfered or frusto-conical surface 68 at the lower end of the valve body chamber 64. A plug 70 is threadably received at the upper end of the chamber 68 and a set screw 72 is threadably received in the central portion of the plug 70. The lower end of the set screw 72 has a guide portion 70 around which a compression spring 76 is positioned. The lower end of the compression spring 76 is received within a cylindrical central chamber 78 in the piston 62. The compression spring 76 thereby acts between the set screw 72 and the piston 74 to normally maintain the piston 74 in a position such that the lower chamfered surface 66 is in sealing engagement with the chamfered surface 68 in the lower portion of the chamber 64.

A circumferential recess or groove 80 is provided in the wall at the lower portion of the chamber 64 immediately above the chamfered surface 68. An outlet 82 to the atmosphere communicates with the groove 80. The outlet 82 by the action of the spring 76 is normally closed from the chamber 64 because of the sealing engagement between the chamfered surfaces 66 and 68. The lower end of the chamber 64 has a diametrical opening 86 passing therethrough. Hose fittings 88 are threadably received within the opposite ends of the opening 86 so as to receive the tubing 26 and 28, shown in FIGURE 1.

By suitable adjustment of the set screw 72, the relief valve 24 is preset to the desired level. When the air pressure in the lower portion of the chamber 64, which communicates with the system air pressure, increases beyond the desired level and acts against the lower end of the piston 62 to overcome the pressure of the spring 76, the piston 62 rises 50 that excessive air pressure is relieved through the groove 80 and outwardly through the relief outlet 82.

By use of the relief valve 24, the system 10 may be operated without fear of causing undue pain or danger to the patient and without fear of bursting the bladders of the pressure relief cuffs 48 or other parts of the system. It is important that the pressure relief valve 24 be preset by the manufacturer and that the relief valve 24 is enclosed within the enclosure or case 58 so that operators of the system 10 can not change the adjustment of the relief valve 24. Preferably, the relief valve is set to relieve air pressure when the pressure in the system exceeds 105 mm. of mercury. The valve body 60 is desirably secured in the case 58 by securement to a support plate 90 by a screw 92. The plate 90 is fastened in any suitable manner within the casing 58.

While in the foregoing there has been provided a detailed description of a particular embodiment of the present invention, it is to be understood that all equivalents obvious to those having skill in the art are to be included within the scope of the invention as claimed.

What we claim and desire to secure by Letters Patent is:

1. In a rotating tourniquet system including means for providing air pressure, four pressure cuffs for securement around each arm and each leg of a patient, means for distributing air pressure to said cuffs from said air pressure means, and valve means for adjusting the pressure in said cufis, the improvement comprising pressure relief valve means in said tourniquet system, said relief valve means being connected between said air pressure distributing means and said air pressure means and being preset to relieve air pressure in said system when the air pressure exceeds a predetermined level.

2. The improvement of claim 1 wherein an enclosure is provided for said pressure relief means so that relief means is normally inaccessible to operators of the equipment.

References Cited UNITED STATES PATENTS 3,167,067 1/1965 Rand 12824 L. W. TRAPP, Primary Examiner US. Cl. X.R. 128327 

